hi, Russell, Tony
Is this patch ignored by you? I do not see any ack for this patch.
Thanks
Janboe Ye
2009/12/3 Tero Kristo <tero.kristo@xxxxxxxxx>:
> From: Tero Kristo <tero.kristo@xxxxxxxxx>
>
> In some ARM architectures, like OMAP3, the VFP context can be lost during
> dynamic sleep cycle. For this purpose, there is now a function
> vfp_pm_save_context() that should be called before the VFP is assumed to
> lose context. Next VFP trap will then restore context automatically.
>
> We need to have the last_VFP_context[cpu] cleared after the save in idle,
> else the restore would fail to restore when it sees that the last_VFP_context
> is same as the current threads vfp_state. This happens when the same
> process/thread traps an exception post idle.
>
> This patch also fixes a potential problem with vfp_pm_suspend(), where
> VFP context can be lost if the current process does not have VFP enabled.
> Fixed by calling vfp_pm_save_context().
>
> Signed-off-by: Tero Kristo <tero.kristo@xxxxxxxxx>
> Cc: Vishwanath Sripathy <vishwanath.bs@xxxxxx>
> Cc: Rajendra Nayak <rnayak@xxxxxx>
> Cc: Richard Woodruff <r-woodruff2@xxxxxx>
> Cc: Peter 'p2' De Schrijver <peter.de-schrijver@xxxxxxxxx>
> ---
> arch/arm/vfp/vfpmodule.c | 28 ++++++++++++++++++++--------
> 1 files changed, 20 insertions(+), 8 deletions(-)
>
> diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c
> index 2d7423a..920a33b 100644
> --- a/arch/arm/vfp/vfpmodule.c
> +++ b/arch/arm/vfp/vfpmodule.c
> @@ -329,22 +329,34 @@ static void vfp_enable(void *unused)
> #ifdef CONFIG_PM
> #include <linux/sysdev.h>
>
> -static int vfp_pm_suspend(struct sys_device *dev, pm_message_t state)
> +void vfp_pm_save_context(void)
> {
> - struct thread_info *ti = current_thread_info();
> u32 fpexc = fmrx(FPEXC);
> + unsigned int cpu = get_cpu();
> +
> + /* Save last_VFP_context if needed */
> + if (last_VFP_context[cpu]) {
> + /* Enable vfp to save context */
> + if (!(fpexc & FPEXC_EN)) {
> + vfp_enable(NULL);
> + fmxr(FPEXC, fpexc | FPEXC_EN);
> + }
>
> - /* if vfp is on, then save state for resumption */
> - if (fpexc & FPEXC_EN) {
> printk(KERN_DEBUG "%s: saving vfp state\n", __func__);
> - vfp_save_state(&ti->vfpstate, fpexc);
> + vfp_save_state(last_VFP_context[cpu], fpexc);
>
> /* disable, just in case */
> - fmxr(FPEXC, fmrx(FPEXC) & ~FPEXC_EN);
> + fmxr(FPEXC, fpexc & ~FPEXC_EN);
> +
> + last_VFP_context[cpu] = NULL;
> }
>
> - /* clear any information we had about last context state */
> - memset(last_VFP_context, 0, sizeof(last_VFP_context));
> + put_cpu();
> +}
> +
> +static int vfp_pm_suspend(struct sys_device *dev, pm_message_t state)
> +{
> + vfp_pm_save_context();
>
> return 0;
> }
> --
> 1.5.4.3
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-omap" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
